tor-spec: Fix error in recognized, and explain better
Recognized is 2 bytes, so it is zero with probability 1 in 2^16, not 1 in 2^32.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information
Recognized is 2 bytes, so it is zero with probability 1 in 2^16, not 1 in 2^32.